Currently, for both wired and wireless communication services, multimedia services have become the major services which operators provide to their to subscribers. In the field of wireless communication, wireless broadcast communication is characterized by larger coverage and high program capacity. The greatest advantage of the wireless broadcast communication consists in its nature of broadcast and capability of point-to-multipoint, such that a high transmission bandwidth can be achieved with a low cost. Thus, the wireless communication broadcast, as an important part of the information/communication industry, plays a critical role in construction of the national information infrastructure and implementation of ubiquitous service as well as in the national information security strategy.
Among a variety of multimedia services, mobile multimedia broadcast service is now regarded by the industry as an important application with a prospect of promotion. Here, the mobile multimedia broadcast service refers to a system enabling small sized, mobile and portable handheld terminals with a screen smaller than 7″, such as mobile phone, PDA, MP3, MP4, digital camera, notebook computer and any other receiving devices, to receive services such as broadcast TV programs and information services anytime and anywhere.
At present, some of such service are provided by the mobile multimedia broadcast based on existing mobile communication networks and streaming media. However, due to the technical limitations (such as bandwidth) of the existing mobile communication networks, the above communication approach cannot further improve the performance of the existing mobile multimedia performance and thus cannot provide satisfactory audience experience to the subscribers. Since the broadcast technology and the broadcast network have their own advantages, such as unlimited receptions once transmitted, low cost and high bandwidth, it is a principle of research and development for mobile multimedia broadcast to provide a high-quality broadcast multimedia service to handheld terminals by cooperation of broadcast networks and communication networks.
The applicant has proposed a system network architecture with a satellite broadcast coverage as a primary part and a terrestrial supplementation network as a secondary part, especially for the scenario in China which has a vast territory, a complicated transmission environment, cities located intensively in the east and sparsely in the west, a huge amount of users and a diversity of service demands. According to this architecture, the characteristics of satellites, such as large coverage, short construction period and high efficiency, are fully utilized to achieve a solution for implementing a country-wise coverage of mobile multimedia broadcast signals cost-effectively and rapidly. Invention patent applications have been filed based on the above technical solutions; cf. Chinese Patent Applications No. 200610113915.9 and No. 200610113916.3. In the disclosures of the above applications, specific technical solutions are provided for mobile multimedia broadcast, including physical layer channel frame structure, channel coding and modulation for the mobile multimedia broadcast.
However, the technical solutions in the above applications generally relate to the mobile multimedia broadcast communication with in a bandwidth of 8 MHz or 2 MHz. With the rapid growth of the global wireless communication business, the contradiction between the supply and the demand for radio frequency resources is increasingly deteriorated. As a special resource essential to wireless communication, the frequency resources are exclusive and multiplexed. That is, within particular time, geographical area and frequency band, the frequency resources, once used, cannot be used by other devices. However, the radio frequencies can be multiplexed and shared given particular time, geographical area and coding condition. There is thus a need for a communication system suitable for different operation bandwidths to allow for different frequency resource assignment situations in individual countries in the world.